Pfizer Withdraws Oxbryta from Global Market Due to Death Risk

Pfizer announced on Wednesday that it will withdraw its sickle cell disease therapy, Oxbryta (voxelotor), from global markets following new data that revealed a higher risk of deaths and complications in patients treated with the drug. According to Pfizer, recent safety data highlighted an "imbalance" in vaso-occlusive crises and mortality events among patients, necessitating further assessment. As a result, the company concluded that the overall benefits of Oxbryta no longer outweigh the associated risks for patients with sickle cell disease.

This decision impacts all active clinical trials and expanded access programs involving Oxbryta. Pfizer has already communicated the new safety concerns and the withdrawal to global health authorities and will continue to review these recent findings.

Aida Habtezion, Pfizer's Chief Medical Officer, emphasized that the decision to withdraw Oxbryta is in the best interest of the patients, underscoring the company's commitment to patient safety and well-being. Patients currently on Oxbryta are advised to consult their physicians about alternative treatment options.

Despite the withdrawal, Pfizer stated that this move is not expected to affect its financial guidance for 2024. However, analysts from Guggenheim Securities noted that while the financial impact might be modest, the development could further aggravate investor frustrations with Pfizer's business development strategies. They indicated that the news might raise questions about Pfizer's ability to sustain growth through 2025-2030, a period when the company faces numerous patent expirations and other challenges to its current growth drivers.

Oxbryta functions as an orally available hemoglobin S polymerization inhibitor, designed to prevent the sickling of red blood cells. Initially approved for treating sickle cell disease (SCD) in November 2019, the drug was brought to market by Global Blood Therapeutics. Pfizer acquired this biotech firm in 2022 for $5.4 billion.

Evan Seigerman, an analyst at BMO Capital Markets, described the withdrawal of Oxbryta as a "significant blow" to patients with SCD, a group that has historically been underserved. Nonetheless, there are new treatment options on the horizon, including two gene therapies that the FDA approved in December 2023: bluebird bio’s Lyfgenia (lovotibeglogene autotemcel) and Vertex Pharmaceuticals and CRISPR Therapeutics’ Casgevy (exagamglogene autotemcel).

Seigerman also pointed out that the new safety signals associated with Oxbryta might lead to increased scrutiny of these newer gene therapies. He suggested that a similar level of caution is likely to be applied to gene therapies for treating sickle cell disorder, although the risk/cost trade-off might differ since patients opting for gene therapies are generally sicker.

In summary, Pfizer's decision to withdraw Oxbryta from the market follows concerning new safety data indicating a higher risk of serious health complications and mortality in patients. While this move aligns with the company's commitment to patient safety, it is expected to have modest financial implications and may further impact investor confidence in Pfizer's business development capabilities. The withdrawal also signifies a setback for patients with sickle cell disease, although promising new gene therapy treatments are becoming available.